Signal averaging is often used in oscilloscopes to reduce the effects of random noise on the input signal. This is done by acquiring the signal several times, averaging the acquired data, and displaying the average. The amount of noise reduction is determined by the number of acquisitions of the input signal that are averaged. That is, as more acquisitions are taken of the input signal and these acquisitions averaged, more noise will be reduced by the averaging process and therefore not be visible on a display of the averaged signal. Prior art oscilloscopes that average the input signal over time often do not graphically indicate their progress toward a target average count. That is, a user of the oscilloscope must know the number of acquisitions the user has requested, the number of the current acquisition being taken, and perform a calculation to derive the progress that is currently being made toward the target number of acquisitions that will be averaged.
One prior art method of displaying the information needed to make this calculation is to display, on one line of the CRT display screen, the current acquisition number being taken and the maximum number of acquisitions that will be taken. This method suffers from two disadvantages, 1) the user must perform a mental calculation to determine the progress, and 2) and entire line of information is used on the screen, thus taking up valuable screen display space.
A second method used in prior art oscilloscopes is to display the current acquisition number on the screen along with the waveform, but to make the target number of acquisitions to be taken available only through a pull down or pop up menu. This method forces the user of the oscilloscope to remember the target number of acquisitions while performing the calculation to determine progress. Furthermore, when the pull down menu is being used, a significant portion of the screen is occupied by the menu.
There is need in the art then for a system to conveniently display the progress being made toward the target number of acquisitions to be averaged. There is a further need for this display method to occupy a minimal portion of the CRT screen display area. Still another need is for the display to provide a visual indication of the percentage of completion toward the target number of acquisitions. The present invention satisfies these needs.